The present invention relates to a surge brake actuator used in transporting a towed vehicle with a towing vehicle. Particularly, the present invention relates to a surge brake actuator for actuating a braking mechanism or system of a towed vehicle.
For towed vehicles, such as trailers, it is common to provide a self-contained hydraulic braking system that operates independently of the braking system on the towing vehicle. A surge brake actuator is usually connected between the towing vehicle and the towed vehicle so that towed vehicle moves with the towing vehicle. In addition, the surge brake actuator permits the towed vehicle to utilize its own braking system when the towing vehicle brakes.
The surge brake actuator generally includes a coupler housing component attached to the towing vehicle and a hydraulic cylinder component that actuates the braking system of the towed vehicle. The surge brake actuator operates such that when the towing vehicle brakes, the forward momentum of the towed vehicle applies a force on the coupler housing attached to the towing vehicle. The hydraulic cylinder utilizes the resultant force on the coupler housing component to actuate the braking system of the towed vehicle. Specifically, the resultant force is translated into fluid pressure within the hydraulic cylinder to activate the braking system of the towed vehicle.
The output pressure of the braking system is a function of the ability of the brake actuator to convert the forces provided by the towing vehicle into hydraulic pressure so as to actuate the braking system of the towed vehicle. This force/pressure ratio is an important component in the ability of an actuator to provide braking pressure to the towed vehicle. To date, normal use of various designs of brake actuators fail to efficiently convert the decelerating force to fluid pressure. Reasons for such inefficient conversion of the decelerating force to fluid pressure include: a build-up of road debris in the actuator; corrosion or rust bonding of actuator components; high frictional loss from actuator components; and coupler housing interference.
In addition, breakaway mechanisms may be incorporated into surge brake actuators. These mechanisms generally operate through a breakaway mechanism, which typically comprises a lanyard having one end operably connected to the brake actuator. In the event that the towed vehicle detaches or breaks away from the towing vehicle during operation, the lanyard typically triggers the braking system of the towed vehicle to stop the towed vehicle.
More specifically, the breakaway mechanism is usually designed so that, when the towed vehicle breaks away or is otherwise disconnected, the lanyard is separated from the surge brake actuator but remains attached to the towing, vehicle. As the towing vehicle pulls the cable, the cable actuates the braking system of the towed vehicle prior to detaching from the surge brake actuator. To prevent the cable from retracting and prematurely releasing the towed vehicle brake, a friction lock is generally used to maintain pressure on the cable. However, such frictional locks occasionally prematurely trigger the braking system of the towed vehicle, causing damage to the surge brake actuator, the towed vehicle, and/or the towing vehicle.
For example, during connection and disconnection of the towed vehicle from the towing vehicle, the lanyard is often pulled or tugged toward the towing vehicle. A slight tug is often enough to slightly actuate the braking system of the towed vehicle. This slight activation can cause excessive wear on the braking system of the towed vehicle and an excessive burden on the towing vehicle, causing decreased fuel mileage and increased maintenance costs. Over time, this excessive burden may cause premature lining wear or overheating of the braking system of the towed vehicle and may eventually cause the braking system to fail in an emergency situation.
Another feature found on certain brake actuators is a reverse lockout assembly. Known reverse lock-out assemblies prevent accidental actuation of the towed vehicle brakes when the towing vehicle backs up or reverses. These known reverse lockout assemblies are not reliable because they allow for the possibility of accidental disengagement while the towing vehicle moves in reverse. Additionally, the design of these reverse lockout assemblies requires a user to manually engage and disengage the reverse lockout assembly. Inherently, this requires a user to exit the towing vehicle to engage the reverse lockout assembly, return to the towing vehicle to reverse the towing vehicle, again exit the vehicle to disengage the reverse lockout assembly, and return once more to the towing vehicle to move the towing vehicle in a forward direction. Obviously, such reverse lockout assemblies are frustrating and time consuming to use.
Thus, it would be beneficial to have a surge brake actuator that can overcome these identified problems. For example, it would be beneficial to have a surge brake actuator having a breakaway mechanism that safely and reliably operates when the actuator decouples from the towing vehicle. In addition, it also would be beneficial to have a surge brake actuator having a reverse lockout assembly that is simple to use and reliably prevents brake actuation when the assembly is engaged and the towing vehicle operates in reverse. It also would be advantageous to have a reverse lockout that reliably disengages when the towing vehicle moves forward.